1. Field of the Invention
This invention relates to a control valve, and particularly to a plug type control valve for controlling the flow of fluids or fluidized materials through a conduit, such as the powered catalyst transfer lines and flue gas vent stacks employed in fluid catalytic cracking systems and in fluid catalytic hydroforming systems in the petroleum refining art; and to a conduits useful with plug valves.
2. Description of the Prior Art
Fluid catalytic methods are used widely in the petroleum and chemical industries. In these methods finely divided catalyst particles, are maintained suspended in a gas in the so-called "fluid state" under reaction conditions. Particles in the fluid state undergo hindered settling, i.e., they act in many ways like a liquid. Thus, they may be conveyed from one vessel to another through a conduit, they develop a pressure head, etc.
Fluid catalytic procedures have made it possible for large units to operate continuously on-stream for extended periods of time under closely controlled conditions. Catalysts in such units in processes where deposition of undesirable coke or other contaminant is encountered during the reaction state may be maintained at a predetermined level by continuously circulating the catalyst from the fluid reactor to a regenerator, where such coke or contaminant is removed, as by oxidative combustion. Fluid units of large capacity, such as a through-put of sixty thousand barrels or more of charge per day, are intended to operate on-stream for periods of as long as a year or more without being shut down.
The present invention is capable of various applications involving high temperature operations in the chemical processing and petroleum refining arts, including use in a converter, such as a fluid catalytic cracking unit or a fluid catalytic hydroforming unit of conventional design, having superimposed contact chambers in which the catalyst is maintained in a state of phase separation comprising an upper diffuse phase and a lower dense pseudo-liquid phase, the catalyst being withdrawn from the lower dense phase of the upper chamber through a vertical internal standpipe and discharged at a low point within the dense phase of the lower chamber and, after suitable treatment in the lower chamber, being returned upwardly through an internal vertical carrier line to the dense phase of the upper chamber.
A continuous cycle flow of catalyst between the chambers is obtained by passing catalyst by gravity flow from the upper chamber to the lower chamber through a standpipe and passing the catalyst from the lower chamber to the upper chamber through a carrier line by injection thereinto a stream of the gas to be contacted in the upper chamber, the continuous flow of the mixture upwardly through the carrier line resulting from the fact that the gas and catalyst form a mixture of lower particle concentration within the carrier line than is present in the dense bed of the catalyst in the lower chamber. In those cases where a regeneration zone is superimposed upon a conversion zone, the gas introduced into the carrier line is ordinarily air or other oxygen-containing gas. In those cases where the conversion zone is superimposed upon the regeneration zone the gas introduced into the carrier line is a stream of vaporous hydrocarbons.
Suitable flow control of catalyst from the standpipe into the dense phase of the lower chamber and from the latter into the carrier line for conveyance into the upper chamber is obtained by the use of plug valves engageable with the lower ends of the transfer lines and having elongated valve stems extending through the vessel wall controlled in their longitudinal movement by external mechanical or manual operating means. Such plug valves find applications in oil refineries in controlling the flow of catalyst into a reaction chamber which is subject to temperature extremes, for example, in the range of 1500.degree. F., as well as in other industrial applications wherein the valves are subject to oppositely directed displacements due to thermal expansion and spring forces.
Plug valves (such as Kellogg Orthoflow Valve, U.S. Pat. No. 2,850,364) are used to control the flow of catalyst to introduce oil feed stock or lift air into a riser line. One problem occurring with the hollow tube plug valve providing lift air through the center hollow section is that the lift air pressure at the inlet of the valve cannot be maintained at a high enough level to overcome the bottom regenerator pressure. Another problem occurring with the hollow tube plug valve providing lift air is that when the lift air flow stops due to failure or stoppage of the air blower (which is an infrequent but regular occurrence) catalyst is dumped from the upper regenerator down through the riser in the hollow section of the plug valve.
There has been a long-felt need to over come the problems associated with the prior art plug valves.
In accordance with 37 C.F.R. .sctn.156, applicant is aware of the following U.S. patent references, copies of which are submitted herewith:
______________________________________ U.S. Pat. No. Inventor Title ______________________________________ 758,118 F. Sticker Sand Blaster 998,111 J. D. Murray Sand Blast Apparatus 1,319,193 K. H. V. Von Porat Feeding Device For Pulverulent Fuel 1,364,532 K. H. V. Von Porat Feeding Device For Pulverulent Fuel in Furnaces 1,566,517 L. H. Bergman Blowing Tank For Pneumatic Transport Systems 2,433,726 C. H. Angell Apparatus for Contacting Fluids with Subdivided Solids 2,664,338 P. W. Cornell Line and Valve System for Fluidized Particle Handling 2,668,755 H. Kershaw et al Plug-Type Control Valve For Fluidized Catalyst Conver- sion System 2,850,364 E. D. Dowling Plug Type Catalyst Control Valve For Orthoflow Systcm 2,901,331 H. J. Held et al Apparatus For Fluid Cataly- tic Reactions 3,315,700 E. C. Greenwood Tubular Jacketed Double Bellows Valve 3,339,577 J. W. Teegarden Valve Construction 3,846,080 J. P. BacLean et al Shielded Tip Access Tube A Reactor Probe 4,518,146 Stinson et al Valve Operator Control System 4,623,119 van der Wiel Plug Valve ______________________________________
U.S. Pat. No. 758,118 (lines 58-68) discloses a sandblast device having a valve of size and formation corresponding to a flared end of a pipe. The pointed end of the valve has an outlet port in line with a passageway extending through a tubular operating rod which is connected to the valve.
U.S. Pat. No. 998,111 (lines 49-65) discloses a sandblast apparatus with a valve having a hollow stem and a conical head.
U.S. Pat. No. 1,319,193 (Page 1, Col. 2, lines 89-110; Page 2, Col. 1, lines 1-38) discloses a device for blowing powderized pulverulent fuel into a furnace. The device has a conical mouth through which the powder flows to a tube which leads to the furnace. The conical mouth is raisable to contact the tube to shut off the powder flow.
U.S. Pat. No. 1,364,532 discloses a variety of valves for use in feeding devices for pulverulent fuel in furnaces.
U.S. Pat. No. 1,566,517 (lines 89-120) discloses a valve with a siding nozzle which reciprocates within a bearing. A stream of air is delivered through the nozzle.
U.S. Pat. No. 2,433,726 discloses an apparatus for conversion of fluid hydrocarbons in contact with subdivided solid catalysts with valves for controlling the flow of solid catalysts (Col. 4, line 36). The valves have a cone or flow restricting member which can seat in the end of a conduit (Col. 6, lines 21-35).
U.S. Pat. No. 2,664,338 discloses a system for fluidized particle handling having a valve with disc-shaped valve members (Col. 6, lines 42-59).
U.S. Pat. Nos. 2,668,755 and 2,805,364 disclose plug valves with hollow injector heads.
U.S. Pat. No. 2,901,331 discloses an apparatus which has a cyclone separator for separating catalyst particles from product or effluent gases. The separator has a trickle valve with a plate for closing off the valve's discharge opening (Col. 3, lines 68-75; Col. 4, lines 1-41).
U.S. Pat. No. 3,315,700 discloses a tubular jacketed double bellows valve.
U.S. Pat. No. 3,339,577 discloses a valve with a stem and a valve plug which is movable to seat in a seat ring.
U.S. Pat. No. 3,846,080 discloses a shielded tip access tube for a reactor probe.
U.S. Pat. No. 4,518,146 discloses a valve operator control system for controlling a plug valve.
U.S. Pat. No. 4,623,119 discloses a valve having a plug connected to slips wherein opening and closing the valve involves both vertical and rotational motion of the plug.
Applicant believes U.S. Pat. Nos. 2,668,755; 2,850,364; and 4,518,146 are pertinent to the present invention.